Evaluation of individual and area-level factors as modifiers of the association between warm-season temperature and pediatric asthma morbidity in Atlanta, GA

• Type of Material: Article
• Authors: Cassandra R. O'Lenick, Emory University; Andrea Winquist, Emory University; Howard Chang, Emory University; Michael R Kramer, Emory University; James A. Mulholland, Georgia Institute of Technology; Andrew Grundstein, University of Georgia; Stefanie Ebelt Sarnat, Emory University
• Language: English
• Date: 2017-07-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.envres.2017.03.021
• Title of Journal or Parent Work: Environmental Research
• ISSN: 0013-9351
• Volume: 156
• Start Page: 132
• End Page: 144
• Grant/Funding Information: This research was supported by the National Institute of Environmental Health Sciences (NIEHS) of the National Institutes of Health (NIH) under Award # R21ES023763.; This research was also made possible by grants to Emory University from the US Environmental Protection Agency (USEPA; R82921301, RD834799), NIEHS (R01ES11294), and the Electric Power Research Institute (EP-P27723/C13172 and EP-P4353/C2124).
• Keywords: EMERGENCY-DEPARTMENT VISITS; SOCIOECONOMIC DEPRIVATION; CASE-CROSSOVER ANALYSIS; Childhood asthma; Temperature; AIR-POLLUTION; HOSPITAL ADMISSIONS; HIGH AMBIENT-TEMPERATURE; HEAT-RELATED MORTALITY; Science & Technology; CARDIOVASCULAR-DISEASES; Public, Environmental & Occupational Health; CLIMATE-CHANGE; Environmental Sciences & Ecology; Effect modification; Time-series; Life Sciences & Biomedicine; Climate change; 7 US CITIES; Environmental Sciences
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Public Health; Environmental Sciences

Abstract

Introduction Previous studies have found associations between respiratory morbidity and high temperatures; however, few studies have explored associations in potentially sensitive sub-populations. Methods We evaluated individual and area-level factors as modifiers of the association between warm-season (May-Sept.) temperature and pediatric respiratory morbidity in Atlanta. Emergency department (ED) visit data were obtained for children, 5–18 years old, with primary diagnoses of asthma or respiratory disease (diagnoses of upper respiratory infections, bronchiolitis, pneumonia, chronic obstructive pulmonary disease, asthma, or wheeze) in 20-county Atlanta during 1993–2012. Daily maximum temperature (Tmax) was acquired from the automated surface observing station at Atlanta Hartsfield International Airport. Poisson generalized linear models were used to estimate rate ratios (RR) between daily Tmax and asthma or respiratory disease ED visits, controlling for time and meteorology. Tmax effects were estimated for single-day lags of 0–6 days, for 3-, 5-, and 7-day moving averages and modeled with cubic terms to allow for non-linear relationships. Effect modification by individual factors (sex, race, insurance status) and area-level socioeconomic status (SES; ZIP code levels of poverty, education, and the neighborhood deprivation index) was examined via stratification. Results Estimated RRs for Tmax and pediatric asthma ED visits were positive and significant for lag days 1–5, with the strongest single day association observed on lag day 2 (RR=1.06, 95% CI: 1.03, 1.09) for a change in Tmax from 27 �C to 32 �C (25th to 75th percentile). For the moving average exposure periods, associations increased as moving average periods increased. We observed stronger RRs between Tmax and asthma among males compared to females, non-white children compared to white children, children with private insurance compared to children with Medicaid, and among children living in high compared to low SES areas. Associations between Tmax and respiratory disease ED visits were weak and non-significant (p-value>0.05). Conclusions Results suggest socio-demographic factors (race/ethnicity, insurance status, and area-level SES) may confer vulnerability to temperature-related pediatric asthma morbidity. Our findings of weaker associations among children with Medicaid compared to other health insurance types and among children living in low compared to high SES areas run counter to our belief that children from disadvantaged households or ZIP codes would be more vulnerable to the respiratory effects of temperature. The potential reasons for these unexpected results are explored in the discussion.